seafloor features (ch.3)

Question 1

Bathymetry

Answer 1

measures the vertical distance from thr ocean surface to mountains, valleys, plains and other sea floor features

Question 2

modern instruments for measuring bathymetry

Answer 2

• side scan sonar
• multi-beam sonar
• seismic reflection profiles

Question 3

hypsographic curve

Answer 3

relationship between height of land and depth of ocean

Question 4

3 major ocean provinces

Answer 4

1. continental margins; shallow areas close to shore; nefitic prov.
2. deep-ocean basins; deep-water farther from land; oceanic or pelagic prov.
3. mid-ocean ridge; submarine mountain range; oceanic or pelagic

Question 5

mid-ocean ridge

Answer 5

• largest cont. mountain chain on earth; 60,000km, 33% of ocean floor
• divergent plate boundary

Question 6

seamount (mid-ocean ridge feature)

Answer 6

tall volcanoes

Question 7

pillow lava (mid-ocean rige feature)

Answer 7

shapes formed when hot basaltic lava quickly cools

Question 8

hydrothermal vents (mid-ocean ridge features)

Answer 8

• sea floor hot springs

- foster unusual deep-ocean ecosystems able to survive without sunflight

Question 9

abyssal plains

Answer 9

• extend from base of continental rise
• some of the deepest flattest parts of earth
• suspension settling of very fine particles

Question 10

Passive (Atlantic-style) continental margins

Answer 10

• not close to any plate boundary
• no major tectonic activity
• ex; east coast of Canada, Arctic

Question 11

Active (pacific-style) plate boundary

Answer 11

• associated with convergent or transform plate boundaries
• much tectonic activity
• ex: pacific ocean

Question 12

convergent active continental margin

Answer 12

• oceanic-continent convergent plate boundaries
• active continental volcanoes
• narrow shelf
• ofshore trench
• ex; western south america

Question 13

transform active margin (continental)

Answer 13

• less common
• tra sform plate boundaries
• linear islands, bank and deep basins close to shore

Question 14

the Ring of Fire

Answer 14

trenches, earthquakes, and volcanes conc along the pacific active margin, karked by convergent boundaries

Question 15

what margins generate ocean trenches

Answer 15

convergent margins

Question 16

continental shelf (continrtal margin)

Answer 16

geologically part of continent, flat zone from shore to shelf break

Question 17

shelf brrak (continental margin)

Answer 17

where marked increase in slope angle occurs

Question 18

continental slope (c0ntinental margin)

Answer 18

where deep ocean basins begin, similar to land mountain ranges, marked by submarine canyons

Question 19

submarine canyons

Answer 19

• narrow, deep, v-shape in profile
• extend to base of continental slope
• carved by turbidity currents

Question 20

turbidity currents

Answer 20

• underwater avalanches mixed with rocks and other deris
• sediment from continental shelf
• moves under influence of gravity
• sediments deposisted at slope base forming layers (turbidites)